Alalcomenaeus

Alalcomenaeus

• North America ( Burgess Shale, Canada)
• North America ( Wheeler Shale, USA )
• Asia ( Maotianshan Shale, PR China )

• Alalcomenaeus cambricus

Alalcomenaeus is an extinct animal species from the Early to Middle Cambrian. The numerous fossils of his representative Alalcomenaeus cambricus suspect leave from the Maotianshan Shale in the Chinese province of Yunnan and the Burgess Shale in British Columbia in Canada that Alalcomenaeus was one of the most common species of animals of its time. Alalcomenaeus is discussed as an early representative of the arachnid - line or crustacean - line.

Occurrence

About 600 copies of Alalcomenaeus cambricus have so far been found as fossils in the Burgess Shale. With an incidence of approximately 1.2 % Alalcomenaeus is one of the most common genera of the biota of the Burgess Shale. Numerous other finds come from the Maotianshan slate in China. Again, he was one of the more common representatives of the so-called Chengjiang Faunengemeinschaft. Other discoveries, such as from the Wheeler Shale, Utah, underline the occurrence and spread of this species of animal in the early to middle Cambrian. In addition, other findings have been described as a Alalcomenaeus illecebrosus kind described their assignment to the genus Alalcomenaeus is not backed up.

Features

Alalcomenaeus cambricus had a length of up to 60 mm. His body consisted of a distinct head shield ( cephalon ), eleven trunk segments ( somites ) and a final Telson and was protected by an exoskeleton. At the head shield Alalcomenaeus wore five eyes of which the two outer ones were stalked. Striking is a few leg - gap -like segmented appendages on the head, also known as Great Appendage ( "big notes " ) are referred to. Each of the 11 body segments wore a pair of leg - gap -like extremities. The mouth at the front of the head was connected to the intestines by lying on the Telson anus.

Behavior

Like most of his close relatives was Alalcomenaeus cambricus probably a predator that fed on other animals. His physique suggests that he was moving floating with the help of her hull and particularly its paddle-like telson.

System

Originally Alalcomenaeus cambricus was viewed as an early descendant of the crustacean line. Based on its anatomy, he was considered the ideal ancestor of today's Kiemenfüßer and Cephalocarida. This concept was in the early 1990s largely discarded. According to cladistic analyzes, the genus Alalcomenaeus is allocated along with other representatives of the so-called Megacheira the class of Arachnomorpha ..